INFLUENCE OF SOIL CONDITIONERS ON SOIL PHYSICAL-PROPERTIES AND MAIZE GROWTH

Laboratory and greenhouse experiments were conducted on a lateritic sa ndy loam soil mixed hyperthermic, Ultic Haplustalf to determine the in fluence of several (natural and synthetic) soil conditioners at differ ent concentrations on soil aggregation, porosity, son water retention, saturated hydraulic conductivity, and crop growth. The conditioners w ere applied in solution at the rates of 0.05, 0.10, and 0.20% by spray ing the solution, followed by mixing with the soil to facilitate aggre gation. Only polyvinyl alcohol with borax and guar gum, guar gum + bor ax, and guar gum alone significantly increased the water-stable aggreg ates (2-4 mm diameter), reduced macropores (>30 mu m), increased water retention capacity, and decreased hydraulic conductivity In general, increasing the concentration further improved the soil physical proper ties. Conditioners significantly increased total dry matter of the pla nts. The maximum increase was obtained with guar gum + borax-treated s oil, and the minimum under polyvinyl alcohol with guar gum and borax a nd lignosulphonate treatments. The natural conditioner guar gum with b orax (1 ppm) and polyvinyl alcohol were superior to synthetic or natur al conditioners alone.